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Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Muchun Song , Oscar Salvador , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Matthew Brost , Joshua Hahn , Rakie Kim , Byungchul Park , Gregory Price , Ying Huang , Alistair Popple , Axel Rasmussen , Yuanchu Xie , Wei Xu , Kemeng Shi , Kairui Song , Nhat Pham , Baoquan He , Chris Li , SeongJae Park , Jason Gunthorpe , Leon Romanovsky , Xu Xin , Chengming Zhou , Jann Horn , Miaohe Lin , Naoya Horiguchi , Pedro Falcato , Pasha Tatashin , Rik van Riel , Harry Yoo , Hugh Dickins , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-s390@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, damon@lists.linux.dev Subject: Re: [PATCH 02/16] mm: introduce leaf entry type and use to simplify leaf entry logic Message-ID: References: <2c75a316f1b91a502fad718de9b1bb151aafe717.1762171281.git.lorenzo.stoakes@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2c75a316f1b91a502fad718de9b1bb151aafe717.1762171281.git.lorenzo.stoakes@oracle.com> X-Rspam-User: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 919E84000D X-Stat-Signature: 83w6ynxin5mgey65ubbaacjc75bcdetm X-HE-Tag: 1762369616-893764 X-HE-Meta: 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 621zOcK2 6hBLFXUV0Zz2h/gGd+RIrN4JBMlCh7Bvji4o/Hp5/X3nkDZhOTQ36mQpQKx2YOp4MsfX78SJdTnXgDoxAEK44ccPIFirsvN+HQZ63dpSFwJaohZs89WvYmRjN1serS+NLpudkqVBwsTcy3q0jGM4mwI8iQo5GvGJsGr3mP89MTNyDDgWULv8Onaan9WRBW6dOD7dYmCuWHhn6FzhcRFv2kjU40Phpb/YNwcflksCfa1h1X+OGZgo87Wfth8kF6X3h13O5KkJU3QjZiFzu+nc+7jvG+2dUeg2wesMscuSwp6dSmawkrmR4sG9/Q0x3jR9EUMou X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Nov 03, 2025 at 12:31:43PM +0000, Lorenzo Stoakes wrote: > The kernel maintains leaf page table entries which contain either: > > - Nothing ('none' entries) > - Present entries (that is stuff the hardware can navigate without fault) > - Everything else that will cause a fault which the kernel handles The problem is that we're already using 'pmd leaf entries' to mean "this is a pointer to a PMD entry rather than a table of PTEs". So I think we need a new name. A boring name would be 'swent' (software entry). An acronym would be SWE. In the XArray I distinguish between pointer entries and value entries -- would calling them value entries work here? Or we could call them something entirely different. Say 'twig'. Or 'cask'.